A PRELIMINARY FISHERY SURVEY OF THEVEMBANAD BACKWATERS I KERALA.

BY

H.P.C. SHETTY.

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CON T E 'N T SPage No.

Introduction • •• • • • 1Topographical Features • •• •• • 2Hydrobiological Features(a) Salinity ••• • • • 3

(b) Sources of pollution • • • • •• 3

(c) Plaakton sad benthos ·.. • •• 3

(d) Commercially important fishes and prawns 4

Fishing grounds, Landing Places, Fishingseasons and Disposal of Catches • • • 4

Fisheries and Fishing Operations(a) Dip net and Stake net fisheries • • • 5(b) Other fisheries ·.. • •• 7

(0) Paddy field prawn fishery •• • 11Estimation of Production • •• • • • 11Administration of Fisheries ••• 11Major Investigational Problems • •• 12Summary • • • ••• 14Acknowledgements • •• ••• 14References • • • • •• 15Appendix • • • ••• 18

CENTRAL INLAND FISHERIES RESEARCH INSTITUTE. BARRACKPORE.

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INTRODUCTION

Boardering the coastline of Kerala there are a largenumber of backwaters, which are connected with the sea by somepermanent and some perLodLc a.I openings and which in associationwith adjoining low-lying lands, paddy fields and the network .of canals form an extensive source of year-round fish supplies,They are believed to be the nursery grounds of several speciesof prawns and fishes of commercial importance and hence afforda rich source of prawn and fish seed. But the r-ec errt. developmentof reolamation proj ects in these areas pose a problem and it is--imperative to assess their effects on fisheries. Further, accor-ding to Pani~kar (1952) there has been a most marked 'depletion'of the fisheries in the backwaters, canals and low-lying areasin Travancore, owing probably to the intensive fishing-that hasbeen ~oing on without replenishment having taken place. Earlier,John (1936) had referred to the indiscriminate fishing methodsand lack of Government oontrol, whioh tend to lead-to deolinein fish populations by destroying breeders and fry.

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But, as yet there is no scientifiO information on thestatus of the fisheries in these waters. The hydrology andplankton of these waters have hardly received any attention,except for the work of George (1958). Likewise, their fish andfisheries have not been studied to any useful extend, eventhough some accounts have appeared regarding the bionomics ofsome fish (Bhaskaran, 1946), or the speoies available (Day, 1865;Pillay, 1929; John, 1936; Silas, 1949 etc). Only the prawnfisheries have been fairly extensively studied by a number ofworkers, notably Menon (1951, 1954, 1955~ 1957 & 1958), Menonand Raman (1961), Panikkar & Menon (1955), Gopinath (1955),George (1959), Panikkar (1937) and Chopra (1943), while aooountsof several fishing gear used in these waters have been given byHornell (1937 & 1950), Gopinath (1953) and in a Government ofIndia Publication (1951).

Therefore, a preliminary survey of the largest piece ofKerala backwaters, the Vembanad backwaters (inoluding theVembanad lake and the Cochin backwaters), was undertaken duringMarch 1959 in order to obtain a general idea of its fisheriesand to identify the problems requiring investigation.

TOPOGRAPHICAL FEATURES

The Vembanad backwaters extend from Cranganore in thenorth to Alleppey in the south, a distance of about 96.5 I~.(see map). The total area of this water mass as shown in theSurvey of India map is roughly 300 Sq.Km. But: an area of about

~ 44 Sq.Km. at its south-eastern corner near Alleppey was foundto have already been reclaimed at the time of survey, therebyredUCing the total area to about 256 Sq.Y~. The northernportion of the backwaters above Aroor is situated in the erst-while Cochln State and is generally referred to as the Cochlnbackwaters, while the southern portion, termed normally as theVembanad lake, lies in the erstwhile Travancore State. In viewof the continuity of this water mass right up to Cranganore,the entire stretch is referred to as the Vembanad baokwaters inthis report. This, along with the Kayamkulam and Ashtamudilakes; forms the more important of the Kerala brackishwaterlakes.

The southern portion of the Vembanad bacbvaters is muchbroader, while the northern portion is narrower and sinuous.The lake runs parallel to the Arabian Sea, to which it is·conneoted in the main at two places, at Coohin & Azhikode, bothin the northern half. Branching off from the main stretch of .backwaters are a number of subsidiary water masses and canals.

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Except at Cochin, where dredging is carried out tofacilitate the movement of ships, these backwaters are essen-tially shallow, with the depth in the fishing grounds varyingfrom one metre near the shore off Vypin Island at its southernend to 7.75 metres off Aroor near the bridge, with a mean depthof about 3.5 metres. Below Munro Island at its southern part,the lake is quite shallow, the depth on an average being justtwo metres only. It is a little deeper between Thannirmukhamand Vaikom (about 5 metres)and for some distance north ofCochin. The nature of the bottom is mostly muddy, with anadmixture of fine sand granules in some places. Off Kumaragam,the bottom consists of mud with a thick deposit of sub-fossillamellibranoh shells, while off Aroor, Manapilli and Azhikodeit is sandy. The depth and nature of the bottom in differentparts of the backwaters are indicated on the map.

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lITD~OBIOLOGICAL FEATURESI

(a) Salinity:Since both connections to the sea are situated in the

northern half of the backwaters, that section is much moresaline than the southern half. At the time of survey (i.e.,during Harch), the water above Chembu-Panavalli area up toAzhikode showed a salinity range varying from 23.31 to 33.55%0,with the maximum at Coch1n, while the waters below Vaikomshowed a gradual decline southwards from 18.44%0 at Vaikomdown to 10.49~0 at the southernmost end of.the lakeotfAlleppy,Panikkar (1937) has stated that these waters become almostfresh and are in a flooded condition from June to Septemberduring the South-;'lestmonsoon and that the water level fallsconsiderably after the north-east monsoon during November, and

_ by December the water is distinctly brackish. TIe further statesthat optimum conditions for the life of brackishwater animals

~ are obtained in these waters from January to March. Localenquiries revealed that the waters south of Thannirmukham remainquite fresh during the period of southwest monsoon.

George (1958) has given an account or' the hydrologicalconditions of the Cochin backwaters as observed at Narakkalbunder canal rod has inferred that monsoon rain forms the mostimportan t fa.ctor influenc ing salinity variat ions. He found bothsalinity and surface temperatures high during the summer monthsand low during. the monsoon months.(b) S~urces of pollution:

The discharge of effluents from the F.A.C.T. factory inAlwaye is believed to contaminate these backwaters. Even thoughthere appears to be some agitation against this, the extent ofthis pollution does not seem to have been determined so far. Asecond likely source of pollution is the coconut husk retting,which 1s done on a large scale at certain places like Palangad,where the water appears darkish, with apparently high turbidity.(0) Plankton and benthos:

The only published re~ort on the plankton of thesebackwaters is by George (1958), who studied the seasonal fluctua-tions in abundance of the various plankters at Narakkal bundercanal and attempted to correlate these fluctuations with thefluctuations in salinity. I!e found a marked marine element in

c the plankton of these waters.

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During the course· of this survey, immense quantitiesof filamentous algae were noticed at the southern end of thelake off Alleppey and these were found to ha:lper the operationof big nets like Peruvala, by making the hauling process verydifficult.(d) Commercially important ,fishes and pra~ms:

A classified list of all the fishes, prawns and crabscollected during the survey is given in the Appendix. Amongthose of major commercial importance may be mentiored threespecies of prawns (Metapen~ dpbsoni, 11.monoceros and Penaeusindicus) and five species of mulets (M1gil ceph~~, M.cunnesius,M.parsia. M.troscheli and M.waigiensis in the upper half ofthe backwaters above Arukutty, and Cock-up (Lates calcarifer),Milk fish (Chanos chanos) and Pearlspot (Etroplus suratensis)in the lower half. In addition to these, the Sciaenid Sciaenacoiter, the Perch Lutianus ~gentimaculatus and the catfishesTachysurus spp. are found in good numbers all along the back-waters. Among those of lesser commercial importance may bementioned Carnax sansun, Tylosurus strongylur~, Hemiramphuscantori, Etroplus maculatus and Scatophagus ~~gus in the lowerstretches and Thrissocles spp., Anchoviella spp. and Eleuthe-ronema tetradactylum in the upper stretches. The occasionaloccurrence of Hilsa (Hilsa ilisha) in shoals in these watershas already been reported by Pillay (1960).

Of the above, the Pearlspot is reported to be availablein its maximum numbers during the rainy season, while maximumcatches of the Cock-up are obtained from January to April. Thecatfish Tachysurus arius is reported to be fished from Decemberto March, wi th the maximum catches obtained during February andMarch. The fishery for Beloniform fishes extends mainly fromDecember to March, while the Milk fish·is reported to be avail-able in good numbers from November to June. The major prawns,being marine species, enter the backwaters as young ones alongwith tides in search of tood, grow there and return to the seafor spawning. They are caught in their maximum numbers duringthe months September to February. The rare occurrence of Hilsareportedly coincides with the high salinity period during Marchand April.

FISHING GROUNDS, LANDING PLACES, FISH:I;NG SEASONSAND DISPOSAL OF CATC.•.lES

Except at Cochin port area, where it is prohibited,fishing is done practically all over the backwaters. HO\1ever,there are concentrations of dip nets and stake nets in certainregions adjoining important fishing villages. Free nets are

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operated all through the lake, but mostly in the waters adjoin-ing the respective fishing villages. Chllese dip nets and stakenets can be seen in large numbers along the banks and acrossthe backwaters respectively from Thannirmukham in the south up-to Cranganore in the north. Both these nets are completelyabsent below Thannirmukham, because of the lack in that regionof strong tidal currents, whieh are necessary for the successfuloperation of these two nets.

There are also no regular landing places, the catohbeing mostly disposed off anywhere near the fishing ground.However, in some places where fishing is done in the watersadjoining the village, the fish is brought to the villageregularly for disposal. Among the important fishing centresmay be mentioned the following from north to south : Cranganore,Azhikode, Munambam, Pallipuram, North Parur, Manapilli, Edavana-kkad, Narakkal. Manjanakad, Malip,uram, Vadutala, Ochanthuruthu,Thevara, Edakochi, Kumbalam, Arakutti, Aroor, Arukutti, Vuppu-turuthu, Chembn, Panavalli, Vaikom, Shertallai, Thannirmukham,Kumaragam and Alleppey.

There is no separate fishing season as such and fishingis done throughout the year; only the abundance of differentspecies varies in different seasons and accordingly there maybe variation in the frequency of operation of the concernedtypes of nets. As for example, Thelikanni vala is used morefrequently in the rainy season when the Pearlspots are availablein tbeir maximum numbers, or a particular type of net m~y beused during a certain season of the year only, as in the caseof Narimeenvala, which is operated for 'Narimeen' (~ates £!l-carifer) during the months February to April only. Further, thesame net with altered mesh size is used during the rainy seasonfor catching skates and rays.

In the majority of places, the catches are disposed oftlocally in fresh condition to individual consumers. Only whenthe catch consists of very small prawns, it may be sun-driedand sold later on. However, in some places like Cochin, Vaikomand Alleppey the catches are mostly sold to merchants. At Cochin,big and medium sized prawns are purchased by the freezing andcanning companies for export to foreign countries. At Vaikom,the catches, speoially the night catches, are purchased by mer-chants from Kottayam, to where they are taken by the first busservice in the morning. Similarly, marchants from Kottayam andChanganacherry frequent the Alleppey and Kumaragam fishinggrounds.

FISHERIES AN~FISHING OPERATIONS.(a) Dip ~et and Stake net fisheries:

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The most striking feature of these backwaters is theextensive dip net and stake net fishing found all along the

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The night catches consist essentially of large andmedium sized prawns~ (mainly Metapenaeus dobsoni. M.monocerosand Penaeus indicusJ, with a sprinkling of several species offish and at times even crabs and cuttle-fish. Among these maybe mentioned the'Sciaenids (Pama p~a, Sciaena s~p.), cat fishes(Tachysurus spp., Mtstus spp., etc. , clupeoids (Thrissoclesapp , , Anchoviella spp., Megalops cyprinoides), Ambassis ap ,,Leiognathus spp., Eleutheronema tetradactylum, Neptunuspelagicus and 5cylla serrata.

The day time catches consist mainly of mullets (Mugilparsia, M.waigiensis, M.troscheli, ~1.cunnesius and M.cephalus),the others present in lesser numbers being Eleutheronematetradaotylum, Scatophagus argus, Thrissocles spp., Anchoviellaspp., Megalops cyprinoides, Sciaenids and cat fishes. The

~ mullets dominate the catches specially in the Cochin part of thebaokwaters. It is gathered that the night prawn catohes by thisnet are at their maximum from November to February and that thedaily oatch may go up to as much as 100 lbs per net.,(it) Stake net fishery:

stretch above 'Phannf.rmukham ; These nets are ess.entially operatedfor prawns and mullets, which contribute to the most importantoommercial fisheries in the northern half of the backwaters.(1) Dip net f1~hery:

The net employed is generally known as the Chinese dipnet or Cheena vala or Kamba vala. It is a stationery balancedle •• r dip net~cated siggly or in groups both along the shoreand near the shore in shallow waters. The structure and mode ofoperation of this net have been adequately described by Hornell(1937), Panikkar (1937) and others. It is operated at nightsmainly for prawns and during the day mainly for mullets. During

.the night operations a petromax is tied just above the net toattract the prawns. The time of operation is usually at theturn'of the tide from low to high, when the current is bestfelt. The greatest concentrations of this net are at and adja-oent to, the·two openings of the lake into the sea at Ernakulamand Azhikode. At Azhikode, these "nets extend even into the seafor some distance (about a furlong) along the shore, south ofthe Periyar river Qouth. ao~s of them can also be seen on eitherside of a narrow stretch of backwaters (about six m.1les long),west of the main bac~vater mass, running southwards from thePeriyar rtver mouth.

The stake net is a type of fixed conioal bag net witha tapered oOd-end, resembling the Been-jal ot Bengal, about20-25 ft. 'in length. It is locally known as the Kutti vala or~ Y!!!. A full description.of its .structure has already beengiven by Hornell (1937). Usually series of these nets are tiedup to stakes planted across the backv{aters, with one net betweenevery two stakes.

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(i) Cast net fishing:Fishing with' cast nets ('Veechu Y1!!A1) goes on through-

out these bacIDvaters, but is specially concentrated in theupper stretches. AI,1 along from Narakkal to Edavanakkad, thestringed variety of cast nets was seen being operated in largenumbers in shallow areas, which are reported to have flatbottom and hence more suitable for operation of small cast nets.Concentrations of this net were also observed from Manapill~ toCherai and at Parur, Pallipuram and Azhikode in the upper stretchesand in the lower stretches at Arukutti, Kumaragam and Alleppey.

The catches in the upper stretches consist mainly ofmetapenaeid prawns, with also a few mullets, engraulids andsciaenids. In the lower stretches, where generally bigger-meshedcast nets are employed, Pearlspots constitute the bulk of thecatches, the others being half-beaks, gobeids etc. The dailycatch is said to vary from 10-80 lbs. and occasionally even upto two maunds, the average daily catch being about 15 lbs. Itis gathered that the catches are the heaviest during the spring

s tides.

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. This net, is permitted to be operated only during theebb tide, in order to prevent the destruction of young ones ofprawns entering the backwaters. It is usually operated at adepth of about 3-5 metres and fishing goes on practicallythroughout the year. It is, however, mntioned by Menon (1955)that stake net fishing remains suspended when there are highfloods during the monaoon months June-August, because of thelikelihood ot swift currents and floating debris damaging thenets. The daily catch varies from a few pounds to about 50-60lbs in favourable seasons. The prawns form the bulk of thecatohes and it is gathered that th~y are obtained in theirmaximum quantities during September and October. The main,speoies of prawns fished by this net are Metapenaeus dobsoni,Penaeus indicus and Metapenaeus monoceros. The fish caught inthis net consist mainly of Clupeoids (Anchoviella spp.,Thrissocles spp., Anodontostoma chacunda etc.) and gobeids.OcoasionallY,eels, Squilla,Sepia.and Octopus are also found inthe catcne a..(b) Other fisheries:

Besides the above two principal fishing gear, whichbelong to the fixed engine category, several others fallingunder the 'free engine' category are operated for differentfishes and prawns. In addition to these, several people areengaged in extensive clam and shell fisheries. A brief accountis given below of the various fisbing operations and theircatches.

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(ii) Canoe-trap fishing:./

A k1n~ of Canoe-trap, termed locally as the Changalapa71-kkal or Changadam 1s in use in the middle and upper stretchesOf"the Venbanad backwaters, operating in shallow regions duringOalm periods for catching pra\vns.and grey mullets. This methodof fishing is based on a knowledge of the habits of some prawnsand mullets, which when frightened leap wildly out of 'the water.

Several workers like Hornell (1937 & 1950), Panikkar(1937) and Gopinath (1953) have given full descriptions of~~adam and its mode of operation. However, there are differ-enoes in these aco ount.s regarding the dragging device, whichas per the author's observations, consists of a cbain attaohedto the bow of each boat, with the two chains joined togetherposteriorly. But acoording to Gopinath (locecit), it oonsistsof a single long chain, with its,two ends attached to the twoboats, while Hornell (1937 & 1950) and Job and Pantulu (1953)have described it as consisting of short pieces of chain, ,connected by lengbts of ro~e. Further, according to Panikkar(1937) and Chopra (£Q.cit.), it is a net that is tied across,between the two canoes and not any chain, and the prawns tryingto swim through are trapped in this net. This may probably bea local variation at the place and time of observation. Again,it is stated by Panikkar (1937), Gopinath (1953) and Menon(1955) that only prawns and shrimps are caught by this method.But as per information gathered during the presnet .survey , eventhough prawns constitute the main catch, mullets are alsoobtained occasionally. Hornell's (1937 & 1950) accounts confirmthis observation •."(iii) Drag net fishing:

Drag net fishing is again resorted to mainly for catch-ing prawns, 'along with which a"few miscellaneous fish likeAnchoviella spp., Ambassis spp., Etroplus spp., gobeids, half-beaks etc. are caught. The drag net commonly seen in thesewaters is known as the Vadi va La , It is a trough-shaped drag netresembling the Khadi-,jalOOf Orissa. It is generally seen inthe middle and lower stretches from Arulmtti down to Thannir-mukham in the main baclITlaters,as well as in the connectedcanals. The details of its structure have already been describedby Hornell (1937). It is operated either singly or in groups oftwo throughout the year during both night and day at the timeof low tide. The catch, is mostly dried and Bold later on.(iv) Bag net fishing:

A kind of bag net called the Karimeen vala is seen inthe lower stretches operating for about six months in a year ,,'from January to June catching Pearlspots. Mullets and prawnsare also caught in lesser numbers. It is a conical bag net

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18 ft. long and 24 ft. across its mouth. It is made of cottonyarn, with the mesh size varying from It'' near the mouth totIt at the cod end. Fishing is done during both the tides. Thenet is fixed to the bottom by two stakes and is hauled upafter about 30-45 minutes. There are floatS on the upper halfof the mouth ~d sinkers on the lower half. There is no openingat the cod end of the net.(v) Trawl net fishing:

.One kind of trawl net called l~onchi y.!!!!! operates inthe ~iddle stretches near Arulrutti for catching big prawns and

.fish. It consists of a rectangular bag, 25 ft. long and 54 ft.across made of 36 no. cotton yarn, with a mesh size varyingfrom 11"-2". During operation this bag is dragged along by twoboats, the mouth being kept distended by floats on the upperhalt and sinkers on the lower.

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(vi) Seine net fishing:Several kinds of boat seines are operating all over

these backwaters for catching a variety of fishes. Among'thesethe Telikannivala and Pattikannivala are the most common. Bothare providea with long scare lines of tender cocooot leaves andare of .imil~r structure, with only the msh size of latterbeing smaller. The catch consists of a number of fishes, amongwhich may be mentioned Caranx sansun, Therapori puta, Etroelusapp,, rnullets, clupeoids, sciaenids and prawns , ,The smafLeat,meshed (t,,) Pattikannivala is without the scare lines and isused for catching prawns and hence termed chammeen vala. Partof the operation of this net consists of dragging ir-wrth twopoles and this probably accounts for Hornell's (1937) inclusionof Telikannivala and Pattikannivala under drag nets. Maximumcatches by Telikannivala are reportedly obtained during therainy season. .

In the middle and lower stretches can be seen aninteresting method of fishing by Roori vala, wherein the ~undsproduced by moving shoals of fishes are made use of for loca-ting their whereabouts and extent. This type of fishing hasbee n fully described recently by Gopinath (1953-), who terns it'fishing by listening in'. According to him one of the twofishermen gets into the water and immerses his head in thewater, while according to the author's observations, thefisherman sits inside the boat and by bending over immerseshis head in the water. The net is generally used as a seine,but at times also as a gill net set across the path of shoals.The catch consists essentially of Tachysurus spp. and occasion-ally some Sciaenids. Surprisingly, Gopinath (loc.eit,) has notmentioned. cat fishes ~ong the oatch of this net. Heavy catohesare reportedly obtained during February-March and the rainyseason.

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A big 1" meshed boat seine called Peru vala is operatedin the lower stretches throughout the year. The catch is miscell-aneous, consisting of a number of fishes and a few prawns. Thisnet is payed out in concentric circles and is hauled up in sucha way that those of-the fishes which are not gilled are encir-cled and brought up.(vii) Gill net fishing:

A large number of gill nets are operated throughout theyear, mostly in the lower stretches, Among them may be mentionedthe Narimeen vala, Odu vala or Poomeen vala, Thiruda vala,Morashu vala and Chavala vala: The Narimeen vala for catchingLates calcarifer is a big net of 6" mesh size, operated generallyduring the months February to April at nights. The same net ieused in the rainy season for catching ska tes and rays, byaltering the mesh size to 12". The Odu vala is a similar net,but with smaller mesh (3") and is operated throughout the year.The catches consist essentially of Chanos chanos and Latesoaloarifer, with al so a good number of Mugil cephal us, Scato-phagus argus, Lutianus argentimaculatus and Sciaena coiter.The Thiruda vala or Paithu vala is a stationery gill net forcatching Mugil cephalus. Morashu vala is .another kind ofstationary surface gill net in the lower stretches for catchingHemiramphus and Tylosurus. It is 'mainly operated during themonths January to March, when these fishes are reported to beavailable in their maximum numbers. Chavala vala is a driftinggill net operated at nights during the rainy-seison and thecatch is similar to that of Ouu vala.

~ (viii) Clam fishery:Large numbers of live clams are available in these

backwaters from a little to the south of Munro Island down toAlleppey and these are fished by a good number of lower stretchfishermen. The catch is generally taken to their respectivevillages, where the clams are boiled, the flesh taken out andsold to consumers, and the enpty shells sold mainly to peoplepreparing lime and to the Travancore Ceraerrt Fao tor-y , The shells

e are also reported to be used in house .construction and main-tenance works, while half-burnt shells and lime are extensivelyused to counteract acidity in paddy fields and lands.(ix) Shell fishery:

In addition to clam fishery, a large number of peopleare engaged in collecting the sub-fossil deposits of lamelli-branch shells found in the back wat ers from Thannirmukham downto Alleppey. These people mostly belong to the Ezhava communityand are from JCumaragarn and its neighbouring villages. Theshells, be Long ing mainly to the genera rvleretrix and Vellor! ta,are given to the cooperative societies at Kumaragal!1, Mohamma,

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Veohchur, Kuttamangalam etc., which sell them to peoplepreparing lime or to the cement factorY~ These shells are alsoutilised in house construction works and for counteractingacidity in paddy fields. In addition to the above people, thepublic sector cement factory at Kottayamis also collectingthe shells for the manufacture of cement. It is reported thatannually about 50 lakh~ tons of shells are collected from theKeraia backwaters, with the season lasting from .,gust to May,the peak period being January to March (Director of Fisheries,Kera1a, 1961).(c) Paddy field prawn fishe~r:

In addition to the rich backwater fisheries for them,the prawns are also cultured extensively in about 8,000-10,000acreS of paddy fields bordering the Vembanad backwaters (Gopi-nath,1955). The annual production from these fields has beenestimated as ranging from 3,000-5,400 tons, of whioh'prawnstorm about 80%, with an average yield of 360-680 Kgm. per acre(Director ot Fisheries, Kerala~ £E.cit.). This flshery has beenfully described by Menon (1954) and-UOpinath (1955). The high-est yield is reportedly obtained in the Parur and Coohin -Kanayannur taluks in.the norther\1 sector.

ESTIMATION OF PRODUCTION

So far, there has been no serious attempt at estima-ting the production from these and other backwaters. The only

~ figures available are those for the estuarine fish farms inthe State. However, Shri M.Krishna Menon (personal communioa-tion) estimates that about 10,000 tons Qf prawns are annuallycaught from the Travancore-Cochin backwaters and connectedcanals.

ADMINISTRATION OF FISlillRIES

Day in his "Fishes of Malabar" (1865) has observed thatat that time there was no tax upon fishermen or on their imple-ments of trade 'either in the "British terri tory or in the nativeState of Cochin", while previously the fishermen had to pay fottheir fishing rights either in kind or by way of taxes or both.At present the fishing rights in the Vembanad backwat.ers arecontrolled by a system of leasing the licensing. The mainstretch of the backwaters, as also the major subsidiary massesare not laasnd out, but the fishing gear operating in them are

~ lioensed. The only type of, rather indirect, leasing, inthese waters is in connection with the fixed engines, whereinthe places allotted for their operation are fixed and

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cannot be changed. But here also a certain licence fee ischarged for each operating net. It is gathered that even if theGovernment wants to take over such locations, due compensationwill have to be paid to the licensee and that the right oferecting stake nets in any particular area is hereditary. Thistype of permanent assignments for fixed engine operations iscommon to the whole of Travancore-Cochin section of the State,while in the Malabar-Kasargode section, where large numbers ofstake nets are operated at the mouths of rivers, they arerenewed from year to year. Likewise, as in the Vembanad back-waters, in the rest of the Travancore-Cochin area also, theGovernment issues licences to individual fisherman for operatingfree fishing implements; but in the Malabar-Kasargode area thefishing rights in public waters are leased out {Govt. of Kerala,1959) •

The licence fee le~ied varies with the type of gear andthe area of'its operation. The licence fee. for stake and dipnets is higher in areas where there is greater tidal influence;Similar licensing is resorted to with regard to the prawn-cultur-ing paddy fields, where also the nagnitude to the licence feedepends on the nature of the field and the tidal conditions inthe adjoining backwaters. Gopinath (1955) has given a detailedaccount of the classification of ~hese fields and the licencefee levied by the Government.

MAJOR INVESTIGNI'IONAL PROBLEMS

Certain canals and minor subdidiarY backwater massesare annually leased out by public auction. The lessees mightthemselves fish in these waters, in which case no separatelicence fee is payable to the Government for the gear operated.At times, the lessees sub-lease these waters to others, fromwhom some fee is obtained for the gear operated.

For a proper utilisation of these important backwaterswith regard to the managenent and conservation of their fish-eries , it is necessary to undertalce some maj or investigationson a systematic basts.

(1) In the first place, there must be suitable machineryfor the collection of fishery statistics, for eatimating totalproduction, catch-per-unit of effort etc., data on which-willbe necessary be tore formulating any development measures.

(2) The suspeoted depletion of the fisheries of thesebackwaters requires immediate detailed investigation. Panikkar(1952) had reported that many areas which previously used toyield appreciable numbers of Etroplus had ceased to be so.

12

Enquiries made during the survey revealed that there has beena progressive reduction in the maximum size of-Etroplus in thelake, which is almost a sure sign of depletion. Further to tak-ing suitable measures to improve the Etroplus fishery, it maybe worthwhile considering implementation of Panikkar's (loo.cit.)suggestion of introducing ormi vorous feeders, which can tol eratewide variations in salinity and can reproduce more rapidly thanStroplus.

(3) The probable effects-of reclamation projects on thefisheries should be ascertained. There are possibilities of thebreeding, nursery and feeding grounds of some commerciallyimportant species of fishing and prawns getting destroyed byextensive reelamation. This will directly affect the prawn andfish seed source, as well as the paddy field prawn culture, inaddition to reducing the production potential of the lakeitself.

(5) It would be interesting to study the effects ofstake net fishing on the comnc r-cLa.Ll.y fisheries of the lake, aswell as of the sea. The net being small-meshed, appreciablequantities of commercially unimportant smaller size-groups arecaught and this may adversely affect some of the commercialfisheries.

(4) It is imperative to investigate the extent ofpollution of these backwaters, resulting from the discharge ofeffluents from the F.A.C.T. factory, Alwaye and from coconuthusk retting in different areas and their effect on fishpopulations.

(6) Suitable neans must be ~orked out either to discour-age the growth or for the removal of the huge quantities offilamentous algae found near Alleppey, to facilitate easy oper-ation of certain big nets like feru vala; unless these algaefbrm the food of any commercially impcrtant fishes. In additionto physically hampering the operation of ?eru vala, these algae,by clogging the meshes of the nets, bring about the destructionot considerable-numbers of fry which are unable to escape. Inthis connection, it may oe mentioned that Cervenka et al.(1959)had tried cOr.1poundsof copper, silver and sodium pentachlore-phenolate to prevent excessive increase of phytoplankton inSedlice reservoir.

(7) Finally, the study of population dyn-amics and biologyof the commercially important species of prawns and fisheswould be of immense help ~n the management of the backwaterfisheries.

13

SUMMARY

A rapid survey of the Vembanad Backwaters in Keralawas carried out in March 1959 in order to obtain a general ideaof its.fisheries resources and to identify the problems requir-ing investigation.

Prawns and mullets dominate the northern half of thebackwaters, while the Cock-up, Bilk fish and Pearlspot pre-dominate in the southern half. Fishi~g is done practically allover the backwaters throughout the year. There are no regularlanding places and the catches are mostly disposed off in freshcondition. Big sized pralvnsare exported to foreign countriesby the freezing and canning companies.

Dip nets and stake ne t-s are extensively operated mainlyfor prawns and the former for mulle ts also,while a variety ofother ne t s are used for catching these and other fishes. Liveclams and sub-fossil lamellibranch shells are fished extensivelyin the southern half. Pralvns are cultured on a large scale inthe paddy fields adjoining these ba ckwaters.

These backwaters are connected to the sea in two places,both in the northern half, which therefore ehows more pronouncedsalinity and tidal conditions. The mean depth is about 3.5 metresand the bottom is mostly muddy. There is apparently some pollu-tion of the waters by the effluents of the F.A.C.T. Factory,Alwaye and by the coconut husk retting in some places.

The fishing rights are controlled by a system of leasingand licensing. For a proper management of the fisheries resour-ces, it is necessary to undertake some detailed investigationslike the collection of catch statistics, popUlation dynamicsand biology of commercially important species and the probableeffects of reclamation projects and water pollution on thefisheries.

ACKNOWLEDGEMENTS

Grateful thanks are due to Dr. T.V.R. Pillay for hiskind help in the initial planning of the survey, constantguidance and helpful suggestions in the preparation of thepaper.. Thanks are also due to Shri V.R. Pantulu for criti-cally going through the manuscript and to Shri T~J. Varghesefor his assistance on the field.

14

R E FER E N C E 8

Bionomics and life history ofEtroplus suratensis (Bloch)with special referenoe tostocking tanks. Proe. IndianSci. Congr. (33rd session;Pt Ill; Abstracts. 8eo.7) :128.

2. Cervenka, R. et.al.(1959) ~ Limnologicka studie 0 nadrzi8edlice u Zeliva - 7. Pris-pevek k metodioe vyberunovych algicidnich sIouoenfn «

8bornvys·. sa. ~. - ~.,Prahs, 3(1~: 247.

1. Bhsskaran, V.K. (1946 )

3. Chopra, B. (1943)

.4. Day, F. (1865)

5. Director of Fisheries,Kerala (1961)

6. George, H.J. (1958)

7. (1959)

8. Gopinath, IC. (1953)

9. (1955)

Prawn .fisheries of India.Proc. Indian §£i. Congr.(30th session; Pt.I!; Presi-dential addresses; Sec.6) :

"153 - 173.Fishes,'of Malabar. (London,Bernard Quaritoh).Kerala Fisheries, .Trivandrum.

Observations on the planktonof the 80chin backwaters.Indian J. Fish, 5(2) :375 - 401.Notes on the bionomics ofthe pr-awn Metapenaelismonoceros Fabricius. Ibid,6(2) : 268 - 279. ----Some interesting mthods offishing in the backwaters ofTravancore. J. Bombay ~.Hist. 80c., 51(2) : 466 - 471.Prawn culture in the ricefields of Travancore-Coohin,India. Proc. Indo-Paoit. Fish.Coun., 6(111) : 419 - 424:---

15

10. Govt. of India (1951)

11. Govt. of Kerala (1959)

12. Bornell, J. (1937)

13. (1950)

14. Job, T.J. !"Pm tulu V.R. (1953)

15. John, O.C, (1936 )

16. Menon, M.K. (1951)

17. (1954)

18. (1955)

19. (1957 )

(1958)20.

Agricultural marketing inIndia : Preliminary guide toIndian fish,Fisheries,methods of fishing and curing,aev.ed. (Delhi, Marketingseries No.66).Administration report of theFisheries department for theyear 1956-57. (Ernakulam).The fishing methods of theMadrAs Pre$idency~ MadrasE!!Q. Bull. 27(3).Fishing in many waters(Cambridge, Univ. pr.)Fish trapping in India~J.Asiat. Soc. §£i., 19(2)175-196. -Freshwater fish and fisheriesof TravancOre. J. Bombay nat ;~. Soc., 38(4) : 702-733.The life-history and bionomicsof the Indian Penaeid prawnMetapenaeus dobsoni Miers.Proc ~ Indo-Paci f. Fi sh , Coun.,3(II) : 80 - 93. ---- ----On the pa.ddy field pr awnfishery to Travancore-Cochlnand an experiment in prawnculture. Ibid, 5(11) : 131.Notes on the bionomics andfishery of the prawn Metapenaeusdobsoni Miers on the South-;1estcoast of India; Indian J.~.,2(1) : 41 - 56. "Contributions to the biologyof penaeid pra\v.nsof theSouth-West coast of India."I. Sex ratio and movements.Ibid, 4(1) : 62-74.Prawn fisheries. Fisheries ofthe West" coast" of India, ed;,by Dr. S.Jones. Pp. 45 - 50.

16

21. Menon, M.K. &Raman, K. (1961)

22. Panlkkar, N.K. (1937)

I

23. (1952)

24. Panikkar, N.K. &Menon, M.K. (1955)

25. Pillay, R.S.N. (1929)

26. Pillay. T.V.R. (1960)

21. Silas, E.G. (1949)

Observations on the Prawn -fishery of the Cochin back-waters with special refe~enceto the Stake net catches.Indian J. Fish., 8(1) : 1-23.The prawn industry of theMalabar coast. d. Bombaynat • last; .§.££.,39(2) :343 - 353.Possibilities of furtherexpansion of "fish and prawncultural practices in India.Curr. Sci., 21(2) : 29 - 33.

Pr-awn fisheries of India.Proc. Indo-Pacif. Fish. Coun.,6(III) : 328 - 336:--- ----

A list of fishes taken in"Travancore frOm 1901-1915.J. Bombay nat , Hi st. Soc.,33(2) : 347 - 379.The occurrence of the Hilsa,Hilsa ilisha Hamilton in theVembanad bac~vaters (Kerala)Sc1. & £!!!.!., 26(1) : 48."On a collection of fish fromTravancore. J. Bombay ~.li!!i. 2££., 48(4) 792.

-: 0 0 0 :-

17

A P PEN D I X

"Thodi"

Classified list of fish,es, pravms and crabs of theVembanad Backwaters. recorded during the survey,

(Malayalam naces, wherever known, areindicated within inverted commas)

*F ISH E S

Class ELASMOBRANCHI.Order LAMNI FORME S

Fami ly SCYLIOmIINIDAE1. Ch1loscyllium ind1cum (Gunther)

SuborderSELACHII

SCYLIORl-UNOIDEISubclass

Class TELEOSTOMI Subclass SCTINOPTERYGIIOrder CLUPEIFOilMES

Suborder CLUPEOIDEIFamily MEGALOPIDAE

2. Mega10ps cyprinoides (Broussonet)Fa~ily CLUPEIDAE

3. Kowa1a coval (Cuvier)4. Hi1sa i1isha (liarnilton)5. Anodontostoma chacunda (IIamilton)-6. Nematalosa nasus (Bloch)7. Dussunieria hasselti Bleeker

"V'alava"

"Kokolichala"Family ENGRAULIDAE

8. Thrissocles purava (Hamilton)9. Thrissoc1es rnalabaricus (Bloch)

10. Thrissocles rnystax (Schneider)r- 11. Anchoviella indica (van Hasselt)

"Challa"" -do-:-"" -do- ""Koluva"

* The Classification followed upto the families is that ofL.S. Berg L"Classification of fishes, both recent andfossil" Trav. Inst. Zool. Acad~ Sci. URSS, 5(2), 1940J

18

Suborder EXOCO~TOIDEIFamily IIEHL;;AH7.HIDAE

25. Hemiramphus limbatus Cuv. & Vale "Morashu"

Suborder CRI"".OCENTROIDEIFamily CHI~OCENTRIDAE

12. Chirocentrus dorab (Forskal)Suborder CHANOIDEI

Family CHANIDAE13. Chanos chanos (Forskal)

Order CypaINIF03.MESSuborder CYP~INOIDEI

Family CYP:"l.IlTIDAE14. Barbus ticto (Hamilton)

Suborder SILU30IDEIFamily ~~IIDAE (Tachysuridae)

15~ Tachysurus macronotacanthus Bleeker16. Tachysurus falcarlu8 (RiCbardson)17. Taobysurus subrostratus (Cuv. & Val.)18. Tachysurus arius (Hm'ilton)19. Tachysurus coelatus (Cuv. & Val.)

Family BAGRIDAE20. Mystus (~1Ystus)gulio (Hamilton)21. Hyatus (Mystus) armatus (Day)

Order ANGUILLIFOm~SSuborder BJGUILLOIDEI

Family ~fWJ.AENESOCIDAE22. Muraenesox cinereus (Forskal)

Family OPHICIITHYIDAE23. Ophichthys microcephalus Day

Order BELONIF03.MESSuborder SCOMB3ROSOCODEI

Family BELONIDAE24. Tylosurus strongylurus (van Hasselt) - "Kola"

"Poomeen"

"Vellakoori"(?)

19

26. Hemiramphus cantor! Bleeker "Morashu"Order CYPRINODONTIFOJ.MES

Suborder CYPRINODONTOIDEIFamily CYPRINODONTIDAE

27. Haplochilus lineatus (Cuv. & Val.)Order MUGILI!1'O:1MES

Suborder MUGILOIDEIFamily MUGILIDAE

28. Mugil cephalus Linnaeus - "Thiruda"29. Mugil cunnesius Cuv. & Vale "Kanambadu"30, Mugil troscheli Bleeker .,31. ~Augil parsia Iiam. Buch.32. Mugil waigiensis Quoy & Gaimard "

33. Mugil poicilus Day34. Mugil belanak Bleeker35. Mugil arnarulus Cuv •.& Vale (? )36. Hugil seheli (Forskal)

Order POLYNEMIFO~1'!ESFamily POLYNEfAIDAE

37. Eleutheronema tetradactylum (Shaw)38. Polynernus paradiseus Linnaeus

Order PERC IF0l1VIESSuborder ?ERCOIDEI

Family Centropo~idae39. Anbassis gyrnnocephalus (Lacepede)40. Anbassis urotaenia Bleeker -41. Lates caloarlter (Bloch)

Fami ly SER:"1ANIDAE42.Serranus waandersi (Day).43. Serranus diacanthus Cuv. & Vale44. Serranus salrnoides (Lacepede)

Family THERAPONIDAE45. Therapon puta Cuv. & Vale

"Vaazhmeen"

"Nm dan""Narimeen"

"Kora"(MeJC;VW )

20

Family SILLAGINIDAE46. Sillago sihana (Forskal)

FaJ!lily C~1.ANGIDAE47. Caranx sansun (Forskal)48. Chorinemus toloo Cuv. & Val.49. ChorineJ!lusmoadetta Cuv. & Vale -50. Trachynotus ovatus (Linnaeus)

ORTrachinotus blochi (Lacepede)

Family LUTIANIDAE51. Lutianus argentinaculatus (Forskal) -52.' Lutianus johnii (Bloch)

Family LOBOTIDAE53. Lobotes surinamensis (Bloch)

Family LEIOGNATHIDAE54. Leiognathus eguulus (Forskal).55. Leiognathus brevirostris (Val.)56. Leiognathus lineolatus (Val.)57. LCiognathus fasciatus (Lacepede)58. Secutor ruconius (Hamilton)

OREquula ruconius (Hamilton)

59. Secutor insidiator (m och )OR

"Vatta"

"Pannachi"

"Chemballi"

"Kavar1"

M,JlMv.

Equula_insidiatrix (Bloch)60. Gerres filnmentosus. Cuv. & Vale -61. Gerres lucidus Cuv.& Val •.62. Gerres oblongus Cuv. & Vale

Family POMADASYIDAE63. Pristipoma hasta (Bloch)64. Pristiporna operculare Playfair65. Pristipoma guoraka (Russell)

Family SClAENIDAE66. Sciaena albida

"Prtrnj i1 "

67. Sciaena glaucus(Day)Day

21

6$. Sciaena axillaris (Cuv. & Val.)69. Sciaena coiter (Hamilton)70, Sciaena carutta (Bloch) (?)71. ~ parna (Hamilton)72. Sciaenoides biautitus (Cantor)

Fa.11y LErdRINIDAE73. Lethrinus reticulatus Cuv. & Vale

Family SPARIDAE74. Chrysophrys berda (Po rslca L}

Family DREPANIDAE75. Drepane punctata (Linnaeus) -

Family SCATOPHAGIDAE76. ScatoEhagus argus (Bloch)

"PundtbuU

IINachcha rI~.Karimeen"

:

Family CICHLIDAE77. Etroplus suratensis (Bloah) ~ "Kar1meen"78, Etroplus maculatus (Bloch) - "Pallathi"

. -Suborder SIGANOIDEI

Family SIGANIDAE (TEUTHIDAE)79. Teuthis margaritifera Gunther80. Teuthis autor Gunther

Suborder GOBIOIDEIFamily GOBIIDAE

81. Trypauchen vagina Bloch & Schneider82. Gobioides caeculus (Bloch & Schneider)83. Glossogobius giuris (Hamilton) "Poot.an"

Suborder COTTOIDEIFamily PLATYCEPHALIDAE

84. Platycephalus insidiator (Forskal)Order PLEUIWNECTIFORMES

Suborder PLEU_ONECTOIDEIFamily SOLEIDAE

85, Synaptura orientalis (Bloch & Schneider)Family CYNOGLOSSIDAE

86. Cynoglossus bengalensis (Bleeker)

22

87. Cynoglossus puntioeps (Richards)88. Cynoglossus lingua Hamilton

Order TETRODONTIFORMES

89. Triacanthus brevirostris Temminck & Schlegel'''Cbapperi'1

Suborder BALISTOIDEIFamily TRIACANTHIDAE

Suborder TETRODONTOIDEIFamily TETRODONTIDAE

Order BATRACHOIDIFORMESFamily BATRACHOIDIDf£ (BATRACHIDAE)

91. Batrachus grunniens (Linnaeus) ItThavalem.een"

90. Tetrodon patoca Hamilton

PRA'.7NS

94. Penaeus carinatus Dana "Kadal ..Konje"

Family PALAEMONIDAE92. Palaemon carcinus Fabricius

Fami~y PENAEIDAE93. Penaeus indicus (M. - Edw.)

95. Metapenaeus dobsoni Miers96. Metapenaeus monoceros Fabricius97. Metapenaeus affinis (M. - Edw.)98. Parapenaeopsis stylifera (M. - Edw.)

Family SERGESTIDAE99. Acetes erythraeus Nobili (?)

23

eRA B ·S

Family PORTUNIDAE100. Scylla serrata {Forskal)101 •.Neptunus (Neptunus) aanguinolentus (Herbst)102. Neptunus (Neptunus) pelagicus (Linnaeus)

-: 0 0 0 : •..

e

.c

24

MZ/am.,.~

fVQrakkol-~-"'"Manjanakad.

Malifurom3':> 4461;lrn

M

Oc.hanthurufhulIyp'"

SCALE

MAP OF VEMBANAD BACKWATERSSHOWING MAIN FISHING CENTRES,NATURE OF THE BOTTOM, DEPTHAND SALINITY.

[ FIGURES 5UFFIXED WITH 'm I INDICATE DEPTH

WHILE PLAIN FIGURES REFER TO SALINITY,

M = MUD') MS":: MUD & SHEllS. 5 = SAND ')

_MS = MUD & FINE SAND, SS = SAND & SHELLS

AND G = GRAVEL~

I INCH=5'5 MILES

(9 KM.)(Arf'lI.)

N